Determination of chromium and molybdenum with 2-(5-bromopyridylazo)-5-diethylaminophenol by reversed-phase liquid chromatography

Abstract

The reversed-phase liquid chromatographic determination of chromium(III) and molybdenum(VI) chelates with 2-(5-bromopyridylazo)-5-diethylaminophenol was investigated. The metal chelates in 50% ethanol solution were separated within 12 min by using methanol-tetrahydrofuran-water (10 + 15 + 75) containing 0.01 M lithium sulphate and 5 × 10^–3M Tris buffer (pH 7.7) as the mobile phase at a flow-rate of 1.0 ml min^–1, and were detected at 600 nm. The detection limits for chromium and molybdenum are 0.066 and 0.12 ng, respectively. The method has been applied to the determination of chromium and molybdenum in alloy steel and waste water samples.